42 
Wisconsin Academy of Sciences , Arts and Letters. 
Annulus double or triple. 
Cells 5-7 ii in diameter 
Cells twice as large 
j B. cylindrica, 2'6. 
I B. flexifolia, 24. 
B. yirescens, 25. 
Nos. 23, 24, 25, 26, with possibly 29, are doubtless forms of one species, 
so that the key will probably break down here. 
§ V. Convolute©. 
Leaves involute on margin. 
Aristulate by excurrent costa.B. agraria, 34. 
Acute or submucronate ...... B. Donnellii, 36. 
Leaves plane on margin or recurved. 
Capsule costate when dry.B. Rani, 35. 
Capsule smooth. 
Leaves acute, costa percurrent . . . . B. convoluta, 32. 
Leaves with hyaline point.B. Closteri, 33. 
§ VI. Tortuosee. 
Leaves long linear, acute, abruptly mucronate . . B. csespitosa, 37. 
Leaves very long acuminate, cuspidate. 
Twisted crispate when dry, above of one layer of cells B. tortnosa, 38. 
Not crispate, brittle, two layers of cells above . . B. fragilis, 39. 
§ VII. Squarrosae. 
Includes but one species. B. sqnarrosa, 40. 
§ VIII. Syntrichiee. 
[B. bi*evipes may be sought here.] 
I. Leaves with a border of thickened cells. 
Marginal cells elongated . . . . . . . B. subulata, 41. 
Marginal cells roundish. B. lampila, 44. 
. II. Leaves not bordered. 
Cells smooth. 
Cells papillose. 
Monoicous. 
Costa percurrent .... 
Costa excurrent into a long (mostly 
hair. 
B. mncronifolia, 43. 
\ B. inermis, 42. 
I B. subulata var. mutica, 41. 
smooth) hyaline 
B. lseyipila, 44. 
